1. Field of the Invention
The present invention relates generally to a plasma processing apparatus and method, and more particularly to an apparatus and method for processing with plasma a semiconductor wafer or an LCD substrate having an uncovered marginal portion on which a photoresist film has been removed.
2. Description of the Related Art
A plasma etching apparatus is known as a processing apparatus, used in processes of manufacturing semiconductor devices, for making gas into plasma and processing a substrate, such as a semiconductor wafer or an LCD substrate, with the plasma.
Jpn. Pat. Appln. KOKAI Publication No. 63-300517 discloses a plasma etching apparatus. According to this publication, a wafer is held by an electrostatic chuck having a diameter greater than that of the wafer and etched by plasma when a wafer supporting surface of the electrostatic chuck is formed of a polyimide resin, an uncovered portion of the supporting surface is etched by plasma and the lifetime of the electrostatic chuck is reduced.
When a wafer, on which a photoresist film is formed, is subjected to a photolithography process as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 1-198026, a marginal portion of the wafer is exposed to light and the resist film on that portion is removed. The process of exposing the marginal portion is performed to prevent generation of particles, which may be generated from the resist film in the marginal portion, when the wafer is handled, e.g., transferred.
However, when the wafer is etched by the plasma etching apparatus as described above after the process of exposing the marginal portion, the marginal portion of the wafer is also etched. If the marginal portion is etched, it may be broken or damaged when the wafer is transferred after the etching.
If the marginal portion becomes rugged due to the etching, particles are trapped in the rugged portion when the wafer is transferred. The trapped particles are dispersed in a process chamber, in which a next process is performed, and adhere to a wafer. As a result, the manufacturing yield is lowered.
If the plasma processing apparatus is a CVD film-forming apparatus, a film adheres to the uncovered marginal portion of the wafer. The film is broken or damaged when the wafer is transferred by transfer means, and dispersed as particles.